Write–in

a candidate or vote for a candidate not listed on the printed ballot but written onto it by the voter:
write-ins may swing the election.
of, relating to, or for such a candidate or vote or a ballot so marked:
a write-in campaign.
to trace or form (characters, letters, words, etc.) on the surface of some material, as with a pen, pencil, or other instrument or means; inscribe:
write your name on the board.
to express or communicate in writing; give a written account of.
to fill in the blank sp-ces of (a printed form) with writing:
to write a check.
to execute or produce by setting down words, figures, etc.:
to write two copies of a letter.
to compose and produce in words or characters duly set down:
to write a letter to a friend.
to produce as author or composer:
to write a sonnet; to write a symphony.
to trace significant characters on, or mark or cover with writing.
to cause to be apparent or unmistakable:
honesty is written on his face.
computers. to transfer (information, data, programs, etc.) from storage to secondary storage or an output medium.
stock exchange. to sell (options).
to underwrite.
to trace or form characters, words, etc., with a pen, pencil, or other instrument or means, or as a pen or the like does:
he writes with a pen.
to write as a profession or occupation: she writes for the daily inquirer.
to express ideas in writing.
to write a letter or letters, or communicate by letter:
write if you get work.
to compose or work as a writer or author.
computers. to write into a secondary storage device or output medium.
write down,

to set down in writing; record; note.
to direct one’s writing to a less intelligent reader or audience:
he writes down to the public.

write in,

to vote for (a candidate not listed on the ballot) by writing his or her name on the ballot.
to include in or add to a text by writing:
do not write in corrections on the galley.
to request something by mail:
if interested, please write in for details.

write off,

to cancel an entry in an account, as an unpaid and uncollectable debt.
to regard as worthless, lost, obsolete, etc.; decide to forget:
to write off their bad experience.
to amortize:
the new equipment was written off in three years.

write out,

to put into writing.
to write in full form; state completely.
to exhaust the capacity or resources of by excessive writing:
he’s just another author who has written himself out.

write up,

to put into writing, especially in full detail:
write up a report.
to present to public notice in a written description or account.
accounting. to make an excessive valuation of (an -sset).

verb (transitive)
to insert in (a doc-ment, form, etc) in writing
(adverb) to write a letter to a company, inst-tution, etc
(adverb) (us)

to vote for (a person not on a ballot) by writing in his name
to cast (a vote) for such a person by writing in his name

noun (us)
the act of voting for a person by writing his name on a ballot
a candidate or vote that has been written in
(as modifier): a write-in campaign
verb writes, writing, wrote, written
to draw or mark (symbols, words, etc) on a surface, usually paper, with a pen, pencil, or other instrument
to describe or record (ideas, experiences, etc) in writing
to compose (a letter) to or correspond regularly with (a person, organization, etc)
(transitive; may take a clause as object) to say or communicate by letter: he wrote that he was on his way
(transitive) (informal, mainly us & canadian) to send a letter to (a person, etc)
to write (words) in cursive as opposed to printed style
(transitive) to be sufficiently familiar with (a specified style, language, etc) to use it in writing
to be the author or composer of (books, music, etc)
(transitive) to fill in the details for (a doc-ment, form, etc)
(transitive) to draw up or draft
(transitive) to produce by writing: he wrote ten pages
(transitive) to show clearly: envy was written all over his face
(transitive) to spell, inscribe, or ent-tle
(transitive) to ordain or prophesy: it is written
(transitive) to sit (an examination)
(intransitive) to produce writing as specified
(computing) to record (data) in a location in a storage device compare read1 (sense 16)
(transitive) compare underwrite (sense 3a)
v.

for men use to write an evill turne in marble stone, but a good turne in the dust. [more, 1513]

to write (something) off (1680s) originally was from accounting; figurative sense is recorded from 1889. write-in “unlisted candidate” is recorded from 1932.
cast a vote by inserting a name not listed on the ballot, as in he asked them to write in his name as a candidate. [ c. 1930 ]
insert in a text or doc-ment, as in please don’t write in your corrections on the printed pages, but list them separately. [ late 1300s ]
communicate with an organization by mail, as in listeners are being asked to write in their requests. [ 1920s ]

write down
write in
write off
write one’s own ticket
write out
write up